There are three forces on the side of life which require no exceptional mental endowment, which are not very rare at present, and might be very common under better social institutions. They are love, the instinct of constructiveness, and the joy of life. All three are checked and enfeebled at present by the conditions under which men live—not only the less outwardly fortunate, but also the majority of the well-to-do. Our institutions rest upon injustice and authority: it is only by closing our hearts against sympathy and our minds against truth that we can endure the oppressions and unfairnesses by which we profit. The conventional conception of what constitutes success leads most men to live a life in which their most vital impulses are sacrificed, and the joy of life is lost in listless weariness. Our economic system compels almost all men to carry out the purposes of others rather than their own, making them feel impotent in action and only able to secure a certain modicum of passive pleasure. All these things destroy the vigor of the community, the expansive affections of individuals, and the power of viewing the world generously. All these things are unnecessary and can be ended by wisdom and courage. If they were ended, the impulsive life of men would become wholly different, and the human race might travel towards a new happiness and a new vigor. To urge this hope is the purpose of these lectures. The impulses and desires of men and women, in so far as they are of real importance in their lives, are not detached one from another, but proceed from a central principle of growth, an instinctive urgency leading them in a certain direction, as trees seek the light. So long as this instinctive movement is not thwarted, whatever misfortunes may occur are not fundamental disasters, and do not produce those distortions which result from interference with natural growth. This intimate center in each human being is what imagination must apprehend if we are to understand him intuitively. It differs from man to man, and determines for each man the type of excellence of which he is capable. The utmost that social institutions can do for a man is to make his own growth free and vigorous: they cannot force him to grow according to the pattern of another man. There are in men some impulses and desires—for example, those towards drugs—which do not grow out of the central principle; such impulses, when they become strong enough to be harmful, have to be checked by self-discipline. Other impulses, though they may grow out of the central principle in the individual, may be injurious to the growth of others, and they need to be checked in the interest of others. But in the main, the impulses which are injurious to others tend to result from thwarted growth, and to be least in those who have been unimpeded in their instinctive development.